Atoms and the periodic table Miss Jan

Atomic structure SLOs understand that different elements have different atoms atoms are made up from protons, neutrons, and electrons relate the number of protons, neutrons, and electrons in an atom to its atomic number and mass number

Part 1 - Atoms

Brainpop erandchemistry/atoms/ 321REQ

Atomic structure (WB page 4) all the different elements have different atoms these atoms are all made up from protons, neutrons, and electrons the numbers of protons, neutrons, and electrons in an atom can be found from its atomic number and mass number

Charges in sub-atomic particles PROTONS NEUTRONS ELECTRONS : positive charge : No charge : negative charge Page 4 WB

Particles in atoms # protons = the atomic number # electrons = the atomic number # neutrons = the mass number – the atomic number

Example Aluminium has 13 protons (+) and 13 electrons (-) Al has a mass N. of 27. The number of neutrons is 14 (27 minus 13). Al Mass N. Atomic N. Symbol of element

Example 2 K (___________) has ____ protons and ____ electrons. K has a mass number of ______. It has _____ neutrons (_____ minus _____). K potassium

The Periodic Table electrons in atoms are arranged in shells (energy levels) the Periodic Table shows these electron arrangements in all atoms you need to learn the electron arrangements of the atoms of the first 20 elements – Quiz later

Electron arrangement Electrons are arranged in shells. Each shell can only hold a certain number of electrons. 1 st shell: 2 electrons 2 nd shell: 8 electrons 3 rd shell: 8 electrons

Page 5 WB ElementSymbolElectronArrangement Hydrogen11 Helium22 Lithium32, 1 Beryllium42, 2 …………….……………….. Potassium192, 8, 8, 1 Calcium20 Complete table for first 20 elements (H  Ca). Use back page of WB or p120 of NMS2 for help.

ElementSymbolElectronsArrangement HydrogenH11 HeliumHe22 LithiumLi32, 1 BerylliumBe42, 2 BoronB52, 3 CarbonC62, 4 NitrogenN72, 5 OxygenO82, 6 FluorineF92, 7 NeonNe102, 8

SodiumNa112, 8, 1 MagnesiumMg122, 8, 2 AluminiumAl132, 8, 3 SiliconSi142, 8, 4 PhosphorusP152, 8, 5 SulphurS162, 8, 6 ChlorineCl172, 8, 7 ArgonAr182, 8, 8 PotassiumK192, 8, 8, 1 CalciumCa202, 8, 8, 2

Sodium (WB page 5) Sodium has: ____ electrons ____ protons ____ neutrons 11 12

WB p5 - Draw the atom diagrams for: Nitrogen 7 protons 7 electrons 7 neutrons Sulfur 16 protons 16 electrons 16 neutrons 7p 7n 16p 16n

13p 14n 8p 8n O 16 8 Al 27 13

WB page 4 practical Metal reaction with water  see video

WB page 4 Name some very reactive elements: sodium, potassium, lithium, magnesium, fluorine, and chlorine. Name some very unreactive elements: gold, silver, platinum, lead, carbon, and nitrogen.

Part 2 – The periodic table

The Periodic Table SLOs understand that electrons in atoms are arranged in shells state the electron arrangement of atoms of the first 20 elements understand that the Periodic Table shows how electrons are arranged in atoms

Periodic table LHS metalsRHS non-metals Staircase between metals and non metals H Transition metals

The Periodic table Rows: “Periods” Columns: “Groups” Metals (Left) form positive ions Non-metals (right) form negative ions

Noble gases Look at the elements present in Group 18 in the periodic table and answer the following questions: a)Write the electron arrangement for He, Ne, and Ar. b)Is there a pattern? c)What does this mean (relate to stability)?

Noble gases Group 18 All have full outer (valence) shells Non-reactive/very stable E.g. Argon is used in light bulbs

Groups and Periods Groups are the vertical columns in the Periodic Table. Periods are the horizontal rows in the Periodic Table.

Metals and Non-metals Most of the elements are metals Metals are on the left of the Periodic Table Non-metals are on the right of the Periodic Table

Metals and Non-metals Metals have 1, 2, or 3 electrons in their outer shells. Metals form positive ions. Non-metals have 5, 6, or 7 electrons in their outer shells. Non-metals form negative ions.

Noble Gases He, Ne, Ar, Kr, Xe, Rn Have full outer shells of electrons and do not react with other elements

Atoms with half full shells - like carbon and silicon - don’t give and take electrons to form ions instead they share electrons in covalent bonds. And in the middle